Traveling merchants have been attacked by vicious robbers. Wasabi, Namida, and Tsubaki of Team 15 are sent to the site of the incident to investigate. Tsubaki finds a clue that seems to point to samurai from her homeland, the Land of Iron. Furthermore, the clue belongs to a certain person that makes Tsubaki tremble in fear. That person is someone that she respected long ago, a fellow apprentice with whom she trained and honed her swordsmanship with—someone with whom Tsubaki shares a certain fate!

The ship carrying Boruto, his friends, and the people of Dotou Island is dead in the water. A shipbuilder Kajiki and his apprentice Ikada happen to pass by and offer to repair the ship at an island of shipbuilders where they live. Upon arriving on the island, Boruto and his friends try to do whatever they can to help while waiting for their ship to be repaired. Meanwhile, in the seas near the Land of Water, a clash between the pirates of the Funato Clan and the Land of Water is becoming unavoidable.